This invention relates to medico-surgical tubes and assemblies.
The invention is more particularly concerned with cuffed medico-surgical tubes, such as, for example, cuffed tracheal tubes in which an inflatable cuff seals the tube with a patient's trachea.
Such cuffed tubes can present a problem in that secretions produced above the cuff in the trachea, or other body channel in which the tube is located, will be prevented from flowing along the channel and will thereby collect above the cuff, providing a site for the accumulation of bacteria and infection.
Various proposals have been made previously for removing such secretions by providing a suction aperture above the cuff. In Heyden U.S. Pat. No. 4,607,635 there is described a tracheal tube having a channel which opens at various locations along its length and through which a suction catheter can be inserted to remove secretions at any desired location above the cuff. In Chester U.S. Pat. No. 4,305,392 there is described a tracheal tube with a bulbous chamber above the cuff in which secretions are collected for removal through a suction lumen extending through the wall of the tube. The problem with both of these tubes is that it is not possible to remove secretions that collect immediately above the cuff. This is because the cuff is ccnventionally attached to the wall of the tube by means of short collars at opposite ends of the cuff, which are adhered to the tube and extend above and below the cuff. The length of the collar above the cuff defines the closest distance by which the suction aperture can be spaced from the cuff, because any attempt to form a suction aperture through the collar would weaken the join of the cuff to the tube and possibly lead to leakage from the cuff. In Porter U.S. 4,840,173 there is suggested a way in which secretions close to the cuff could be removed, by providing a suction tube which projects over the proximal collar of the cuff. This, however, would have the disadvantage of being relatively complex and expensive to make and provides an undesirable projection from the side of the tube which could irritate the delicate surface of the trachea. There is also the risk that the end of the suction tube may damage the cuff or become blocked by the cuff. This risk can be reduced by making the upper end of the cuff more rigid, but this is a further complication in the construction of the tube.